Revert "sigh. Typehints are pretty useless if you can't use a base class."

This reverts commit dfa3e2fce83638a4cc61114284b0de01728a4a12.
of course, it helps if we type hint with the *correct* parent class.
Don't access the PolKey value if we know we don't have one.
Fix variable name, add declaration/phpdoc
Avoid undefined variable warnings.
Add @todo
CLASS isn't used (or needed) in EAS >= 12.0 GETITEMESTIMATE requests.
Merge branch 'master' into horde_activesync_3_0